Galena
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Sommaire
COLOR
White. Takes a rather poor polish. Because of the cleavage, typical triangular pits are difficult to avoid.
REFLECTANCE
Rather high. About the same as for chalcopyrite (slightly lower). Lower than pyrite.
ANISOTROPISM
Isotropic, but it may polarize rather distinctly, because of the presence of antimony, bismuth or silver in the structure.
TEXTURE
The cleavage is distinct, causing triangular pits during polishing. Galena contains abundant small inclusions which may be tetrahedrite-tennantite (often freibergite), bournonite, freieslebenite, ruby or black silvers, argyrodite, or canfieldite. It is sometimes replaced by argentite and covellite, both associated with cerussite or anglesite.
ASSOCIATED MINERALS
Almost all the minerals, but especially sphalerite, pyrite, chalcopyrite, tetrahedrite-tennantite, bournonite, pyrargyrite, argentite, arsenopyrite, lead sulfosalts, pyrrhotite, magnetite.
CRITERIA OF DETERMINATION
The rather high reflectance and triangular pits are strongly characteristic. So is the association with sphalerite and pyrite. Altaite also displays a few triangular pits but its reflectance is much higher. May be confused with clausthalite but the latter is slightly more reflective. This is quite noticeable in contact with chalcopyrite, which is slightly more reflective than galena and somewhat less than clausthalite.
Source
ATLAS OF ORE MINERALS (P. Picot and Z. Johan)
